Even though there are over one million apps in the Windows Store, Microsoft is saying that the apps will “use one or more ad formats from among banner, interstitial banner, interstitial video and native ads to monetize.” To qualify, the apps in the program need to have a minimum guaranteed daily ad request volume, high viewability standards, and not have any fraudulent activity. Here is a bit more on what Microsoft is saying about the program.

These are top apps and games with a globally distributed audience that is highly engaged, have identifiable users and are viewability certified​. The full list of qualifying criteria is as follows:

Minimum guaranteed daily ad request volume

High viewability rate for impressions

Good quality clicks contributing to a minimum CTR across all ad formats

Only IAB standard ad sizes and no hidden ads

Clean placement of banners – not adjacent, no using ad units across multiple apps

Clear defined user flow to the point where the video and/or interstitial banner ad is shown, no pre-caching

Controlled ad refresh behavior so that the ads returned from the mediation server are always played

Great Store presence with clear app descriptions, high fidelity screenshots and icons uploaded to the Store along with a video trailer (preferable)

Apps submitted to this program go through a rigorous manual review process, part of which make sure that ads are places so the user will not unintentionally click on them. Apps are also monitored so the app usage can not drop over time. Any content uploaded as part of the Store submission is automatically used to showcase premium apps. More information on the program is available here.